Sintering furnace for components made of sintered material, in particular, dental components

Patent metadata

Field	Value
Publication number	US-10948235-B2
Application number	US-201615550401-A
Country	US
Kind code	B2
Filing date	Feb 12, 2016
Priority date	Feb 12, 2015
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

The invention relates to a sintering furnace for components made of a sintered material, in particular for dental components, comprising a furnace chamber having a chamber volume (VK) and a chamber inner surface (OK), wherein a heat-up device, a receiving space having a gross volume (VB) located in the chamber volume (VK) and delimited by the heat-up device, and a useful region having a useful volume (VN) located in the gross volume (VB), are disposed in the furnace chamber. The furnace chamber has an outer wall consisting of a plurality of walls having a wall portion to be opened for introduction into the receiving space of a component to be sintered and having an object volume (VO). In the furnace chamber the heat-up device has a thermal radiator having a radiation field which radiator is disposed on at least one side of the receiving space. Said thermal radiator has a specific resistance of 0.1 Ωmm 2 /m to 1,000,000 Ωmm 2 /m and has a total surface, the maximum of which is three times the chamber inner surface (OK). With this sintering furnace a heat-up temperature of at least 1100° C. can be achieved within 5 minutes at a maximum power input of 1.5 kW.

First claim

The invention claimed is:

1. A sintering furnace for components made of a sintered material comprising:
a furnace chamber having a chamber volume (VK) and a chamber inner surface area(OK),
wherein a heating device, a receiving space having a gross volume (VB) located in the chamber volume (VK) and delimited by the heating device, and a useful region having a useful volume (VN) located in the gross volume (VB) are arranged in the furnace chamber, and
wherein the furnace chamber has an outer wall including a plurality of walls having at least one wall section to be opened for introducing a component to be sintered into the receiving space,
wherein the heating device in the furnace chamber contains at least one thermal radiator, which has a specific resistance ranging from 0.1 Ωmm 2 /m to 1,000,000 Ωmm 2 /m and a total surface area that is at between 1 and 3 times the chamber inner surface area (OK).

2. The sintering furnace according to claim 1 , wherein the chamber volume (VK) of the sintering furnace is between 50 cm 3 and 200 cm 3 .

3. The sintering furnace according to claim 1 , wherein the maximum total surface area of the thermal radiator is not larger than 400 cm 2 .

4. The sintering furnace according to claim 1 , wherein the object volume (VO) is at most 20×20×40 mm 3 .

5. The sintering furnace according to claim 1 , wherein the thermal radiator is heated in an inductive fashion.

6. The sintering furnace according to claim 1 , wherein the heating device consists of graphite, MoSi 2 , SiC, or glassy carbon.

7. The sintering furnace according to claim 1 , wherein the outer wall has a chamber inner wall that is impermeable and/or reflective to the radiation field.

8. The sintering furnace according to claim 7 , wherein the chamber inner wall has a reflective coating.

9. The sintering furnace according to claim 7 , wherein the chamber inner wall is designed as a reflector.

10. The sintering furnace according to claim 1 , wherein the thermal radiator is heated in a resistive fashion.

11. The sintering furnace according to claim 1 , wherein the thermal radiator of the heating device has a heating rate in the useful region of at least 200 K/min at 20° C.

12. The sintering furnace according to claim 1 , wherein the useful volume (VN) is at most 20×20×40 mm 3 and that the dimensions of the useful volume (VN) are at most 20 mm×20 mm×40 mm.

13. The sintering furnace according to claim 1 , wherein the thermal radiator is designed as a crucible ( 11 ).

14. The sintering furnace according to claim 1 , wherein the sintered material is for one or more dental components.

15. The sintering furnace according to claim 12 , wherein the one or more dental components are made of ceramic.

16. The sintering furnace according to claim 1 , wherein the total surface area is at most 2.5 times the chamber inner surface area (OK).

Assignees

• Dentsply Sirona Inc

Inventors

• Fornoff Peter
• Schmidt Christian

Classifications

• F27D99/0006

  Electric heating elements or system · CPC title

• F27D11/06

  Induction heating, i.e. in which the material being heated, or its container or elements embodied therein, form the secondary of a transformer · CPC title

• F27D11/02

  Ohmic resistance heating · CPC title

• F27B17/025 Primary

  for dental workpieces · CPC title

• F27B17/0075

  Heating devices therefor · CPC title